The video above is not camera magic – I actually poured a bottle of water into a room-temperature glass and watched it instantly turn into ice. I stumbled upon this phenomenon when I was experimenting with the optimal temperature at which to serve Pabst Blue Ribbon beer. Long ago, I modified the freezer in my basement to maintain precise temperature control using a PID controller. Over the past few weeks, I’ve been sampling cans of PBR at different temperatures. Incidentally, I have concluded that PBR is best served right around –8.5C. At that temperature, the beer is still liquid, but has a small amount of ice crystal formation (which is just delightful). I just happened to have some small bottles of Arrowhead water in the freezer and I noticed that a few of the bottles remained liquid while others were already frozen solid. I wondered if these bottles might be supercooled: chilled beyond their freezing point but not yet frozen because the ice didn’t have a nucleation point from which to form. Turns out, they were.